Recently, there have been concerted efforts to develop and manufacture microfluidic systems to perform various chemical and biochemical analyses and syntheses, both for preparative and analytical applications. The goal to make such devices arises because of the significant benefits that can be realized from miniaturization with respect to analyses and syntheses conducted on a macro scale. Such benefits include a substantial reduction in time, cost and the space requirements for the devices utilized to conduct the analysis or synthesis. Additionally, microfluidic devices have the potential to be adapted for use with automated systems, thereby providing the additional benefits of further cost reductions and decreased operator errors because of the reduction in human involvement. Microfluidic devices have been proposed for use in a variety of applications, including, for instance, capillary electrophoresis, gas chromatography and cell separations.
However, realization of these benefits has often been thwarted because of various complications associated with the microfluidic devices that have thus far been manufactured. For instance, many of the current microfluidic devices are manufactured from silica-based substrates; these materials are difficult and complicated to machine and devices made from such materials are fragile. Furthermore, transport of fluid through many existing microfluidic devices requires regulation of complicated electrical fields to transport fluids in a controlled fashion through the device.
Thus, in view of the foregoing benefits that can be achieved with microfluidic devices but the current limitations of existing devices, there remains a need for microfluidic devices designed for use in conducting a variety of chemical and biochemical analyses. Because of its importance in modem biochemistry, there is a particular need for devices that can be utilized to conduct a variety of nucleic acid amplification reactions, while having sufficient versatility for use in other types of analyses as well.
Devices with the ability to conduct nucleic acid amplifications would have diverse utilities. For example, such devices could be used as an analytical tool to determine whether a particular target nucleic acid of interest is present or absent in a sample. Thus, the devices could be utilized to test for the presence of particular pathogens (e.g., viruses, bacteria or fungi), and for identification purposes (e.g., paternity and forensic applications). Such devices could also be utilized to detect or characterize specific nucleic acids previously correlated with particular diseases or genetic disorders. When used as analytical tools, the devices could also be utilized to conduct genotyping analyses and gene expression analyses (e.g., differential gene expression studies). Alternatively, the devices can be used in a preparative fashion to amplify sufficient nucleic acid for further analysis such as sequencing of amplified product, cell-typing, DNA fingerprinting and the like. Amplified products can also be used in various genetic engineering applications, such as insertion into a vector that can then be used to transform cells for the production of a desired protein product.